The U.S. media will occasionally challenge facts presented by the White House, but rarely will it challenge the President's basic credibility when he's talking to Americans about a threat to national security. He is, after all, the Commander-in-Chief, and privy to the nation's best intelligence. At the U.N. General Assembly, however, President Bush's warnings to Iran to "abandon its nuclear weapons ambitions," and his cloaking of the invasion of Iraq as part of a march of freedom in the region, are likely to be greeted far more skeptically.

U.N. Secretary General Kofi Annan on Monday warned that Iraq is teetering on the brink of collapse as a nation-state, and more than 40,000 Iraqi civilians have been killed since the U.S. invasion that has turned the country into the fulcrum of regional instability, sectarian conflict and terrorism. So, President Bush's audience at the U.N. General Assembly on Tuesday cannot help but recall his address to the same forum four years ago, when he made a case for war with Iraq based on a litany of what turned out to be spurious claims concerning active nuclear and chemical weapons programs and ties with al-Qaeda.

Bush's charge that Iran has "nuclear weapons ambitions," for one thing, is not an established fact at the U.N. Iranian leaders insist they have no interest in pursuing nuclear weapons, and simply seek to build all aspects of an atomic energy program that are permitted under the Non-Proliferation Treaty. If they were to do so, of course, they would be well within reach of bomb-making capacity  and that, together with concerns over parts of the program that were undeclared until they were later exposed, has prompted the Security Council to ask Iran to voluntarily refrain from uranium enrichment until it has convinced the world it harbors no secret weapons ambitions. Still, while the IAEA, whose inspectors monitor Iran's nuclear activities, has expressed concerns and demanded more clarity over certain aspects of the program, it has found no evidence thus far of a nuclear weapons program in Iran.

Moreover, in negotiating with the Europeans, Iran has expressed a willingness to create additional mechanisms to satisfy the international community's concerns  while maintaining its right, in principle, to enrich uranium. And that's an issue on which it gets considerable support from the developing world. In short, much of the world remains to be convinced that Iran actually harbors the "nuclear weapons ambitions" alleged by President Bush. And the fact that these allegations are coming from the same man who started a war on the basis of a series of claims against Iraq that later were proved false does not help his case.